Intrusion alarm systems of the type known in the prior art are usually relatively large, expensive and cumbersome and require considerable time and technical expertise to install in that they require in-the-wall wiring. Consequently, such systems have not been widely accepted for residential use even though the need for intrusion alarm systems is mounting.
There are several desirable features of intrusion alarm systems, and some of these features are found in some prior art systems, but they are not found in all such systems. These features include protection against false alarms caused by transients in the public power supply, courtesy lighting when an entrance door is opened to facilitate entrance to and egress from the premises, battery backup in the event of a power failure, automatic alarm set on power-up after a power failure, and isolation of the alarm circuitry from the public power lines.
An added feature of an intrusion alarm system which would be highly desirable would be the adaptability of the system to pre-existing structures in a fast and simple manner such that a high degree of expertise is not required to install the system whereby the average home or apartment owner could readily install the system himself.